Knowledge Base
Harmonic Distortion
The presence of frequencies in an electrical signal that are integer multiples of the fundamental frequency, causing power quality problems.
Harmonic distortion occurs when the waveform of electrical current or voltage deviates from a pure sinusoidal shape. Harmonics are frequency components at integer multiples of the fundamental frequency (50 Hz or 60 Hz).
Sources
- Variable frequency drives (VFDs)
- Switch-mode power supplies
- Arc furnaces
- Welding equipment
Effects
- Overheating of transformers and cables
- Nuisance tripping of circuit breakers
- Capacitor bank failure
- Increased energy losses
Mitigation
Reactors are one of the most effective solutions for harmonic mitigation. Line reactors on VFD inputs typically reduce total harmonic distortion (THD) from over 80% to around 35–40%.